High-resolution two-dimensional electrophoresis constitues the most powerful tool available for the comprehensive analysis of complex protein mixtures. The technique has proved extremely useful in a variety of areas including comparison of cell types, comparison of species, analysis of differentiation and the search for genetic variants. In many applications, it is necessary to examine moderately large numbers of samples under conditions which provide very high analytical reproducibility. Such reproducibility could best be achieved using automated systems for the production of both first- and second- dimension gels. This proposal deals with the development of a microcomputer-controlled pumping device and associated gel-forming hardware for the purpose of producing large numbers of very reproducible SDS acrylamide gradient slab gels. This device can make a major contribution towards standardizing the 2-D electrophoretic technique, and thus facilitate the construction and use of comprehensive Protein Indexes.